Optical disc apparatus

ABSTRACT

In the optical disc apparatus according to the present invention, the CPU  113  is operated to execute a control program stored in the ROM  112  to calculate a reproduction time at the time point when the power supply was turned off based on parameters after reading out from the DRAM  111  the parameters at the time point when the power supply was turned off. The CPU  113  is then operated to execute the control program stored in the ROM  112  to produce a control signal to have a display unit, not shown, display the reproduction time thus calculated, and calculate a reproduction position at the time point when the power supply was turned off based on parameters indicative of the address number and produce a control signal to have the reproduction of the reproduction information such as, for example, audio data and image data resumed.

THIS APPLICATION IS A U.S. NATIONAL PHASE APPLICATION OF PCTINTERNATIONAL APPLICATION PCT/JP2003/015924.

TECHNICAL FIELD OF THE INVENTION

The present invention relates to an optical disc apparatus for resumingreproduction of information recorded on an optical disc, and moreparticularly to an optical disc apparatus for obtaining reproductiontime information to resume reproduction of compression audio informationrecorded on an optical disc based on the reproduction time informationin the event that power supply is turned off and then turned on whilereproducing the compressed audio information recorded on the opticaldisc even though the address information of the compressed audioinformation has no reproduction time information.

DESCRIPTION OF THE RELATED ART

Up until now, there have been proposed a wide variety of optical discapparatuses for reproducing information recorded on an optical disc. Onetypical example of the conventionally known optical disc apparatus isdisclosed in, for example, Japanese Patent Laid-Open Publication No.2002-230781 (see columns 0005 and 0006). The conventional optical discapparatus herein disclosed comprises a storage unit for storing addressinformation indicative of a reproduction position of an optical discwhile reproducing data such as, for example, music data, image data, orthe like, hereinafter simply referred to as “data”, recorded on anoptical disc, and is designed to start reproduction of data recorded onthe optical disc from the reproduction position immediately prior to thetime point when power supply was turned off based on the addressinformation stored in the storage unit after the conventional opticaldisc apparatus is rebooted in the event that the power supply is turnedoff and then turned on while reproducing the data recorded on theoptical disc. The operation of starting reproduction of data recorded onthe optical disc from the reproduction point immediately prior to thetime point when the power supply was turned off will be hereinaftersimply referred to as the operation of “resuming reproduction”. Theconventional optical disc apparatus as previously mentioned isfrequently used as an in-vehicle apparatus to be provided in anautomotive vehicle and adapted to have a battery supply power to thestorage unit to have the information remained intact in the storage unitin the event that accessory power supply (ACC power supply) is turnedoff.

Compressed audio data represented by, for example, MP3 (MPEG-1 AudioLayer-3) emerged in recent years, may not include information on areproduction time, hereinlater simply referred to as “reproduction timeinformation”, in its address information of the optical disc. Asdescribed in the above, the conventional optical disc apparatus aspreviously mentioned, however, is simply designed to start reproductionof data recorded on the optical disc from the reproduction positionimmediately prior to the time point when power supply was turned offbased on the address information stored in the storage unit after theconventional optical disc apparatus is rebooted in the event that thepower supply is turned off and then turned on while reproducing the datarecorded on the optical disc, resulting from the fact that theconventional optical disc apparatus can not extract the reproductiontime information from the address information immediately prior to thetime point when power supply was turned off. This leads to the fact thatthe conventional optical disc apparatus encounters a drawback in thatthe conventional optical disc apparatus tends to obtain no reproductiontime information and thus start reproduction of data recorded on theoptical disc from the beginning.

The present invention is made for the purpose of overcoming the abovementioned drawback, and it is therefore an object of the presentinvention to provide an optical disc apparatus which can obtain thereproduction time information after the power supply is restored even inthe case that the power supply is turned off while reproducingcompression audio signal recorded on the optical disc having noreproduction time information in its address information.

DISCLOSURE OF THE INVENTION

In accordance a first aspect of the present invention, there is providedan optical disc apparatus, comprising; an optical unit for projecting alaser light to an optical disc and converting a reflection lightreflected from the optical disc into an electrical signal; signalprocessing means for processing the electrical signal from the opticalunit to have the electrical signal converted into reproductioninformation required for reproduction; parameter storage means forstoring therein a parameter contained in the reproduction informationfrom the signal processing means; and reproduction time computing meansfor computing a reproduction time based on the parameter stored in theparameter storage means. The reproduction information herein used isintended to mean data required for reproduction such as, for example,music data, image data, and the like. The parameter herein used isintended to mean information on address number, bit rate,monaural/stereo and the like.

In accordance with the above construction, the optical disc apparatusaccording to the present invention can obtain reproduction timeinformation after the power supply is restored even in the case that thepower supply is turned off while reproducing compression audio signalrecorded on the optical disc having no reproduction time information inits address information, resulting from the fact that the optical discapparatus is operative to calculate a reproduction time based on theparameter contained in the reproduction information.

In accordance with a second aspect of the present invention, theaforementioned optical disc apparatus may further comprise optical discreproduction means for determining a reproduction start position basedon the parameter stored in the parameter storage means.

In accordance with the above construction, the optical disc apparatusaccording to the present invention can obtain reproduction timeinformation and resume reproduction of the optical disc after the powersupply is restored even in the case that the power supply is turned offwhile reproducing compression audio signal recorded on the optical dischaving no reproduction time information in its address information,resulting from the fact that the optical disc apparatus is operative todetermine the reproduction start position based on the parametercontained in the reproduction information stored in the parameterstorage means.

In accordance with a third aspect of the present invention, theaforementioned optical disc apparatus may further comprise reproductiontime displaying means for displaying the reproduction time based oninformation on the reproduction time computed by the reproduction timecomputing means.

In accordance with the above construction, the optical disc apparatusaccording to the present invention can obtain reproduction timeinformation and display the reproduction time after the power supply isrestored even in the case that the power supply is turned off whilereproducing compression audio signal recorded on the optical disc havingno reproduction time information in its address information, resultingfrom the fact that the optical disc apparatus is operative to calculatea reproduction time based on the parameter, such as, for example,information on address number, bit rate, and the like, contained in thereproduction information.

In accordance with a fourth aspect of the present invention, theaforementioned optical disc apparatus may be mounted on an automotivevehicle, and in which the reproduction time computing means may beoperative to read out the parameter stored in the parameter storagemeans to calculate a reproduction time at the time point when anaccessory power supply was turned off and the optical disc reproductionmeans may be operative to determine a reproduction start positionsubstantially at the time point when the accessory power supply wasturned off in the event that the accessory power supply was turned offwhile reproducing said optical disc and then turned on.

In accordance with the above construction, the optical disc apparatusaccording to the present invention can reproduce and stop reproducinginformation recorded on the optical disc whenever the ignition key isoperated and the accessory power supply is turned on and off, andcalculate a reproduction time at the time point when the ignition keywas turned off and thus the accessory power supply was turned off beforeresuming reproduction of the information recorded on the optical disc inthe case that the accessory power supply is restored. This leads to thefact that the optical disc apparatus according to the present inventionthus constructed can obtain the reproduction time information after theaccessory power supply is restored and resume reproduction ofinformation even in the case that the accessory power supply is turnedoff while reproducing compression audio signal recorded on the opticaldisc having no reproduction time information in its address information.

In accordance with a fifth aspect of the present invention, theaforementioned optical disc apparatus may be operatively connected to anaudio equipment operative to selectively assume a plurality of operationmodes including an optical disc operation mode having the optical discreproduced. In the aforementioned optical disc apparatus, thereproduction time computing means may be operative to read out theparameter stored in the parameter storage means to calculate areproduction time at the time point when the audio equipment switches toan operation mode other than the optical disc operation mode from theoptical disc operation mode and the optical disc reproduction means isoperative to determine a reproduction start position substantially atthe time point when the audio equipment switches to an operation modeother than the optical disc operation mode from the optical discoperation mode in the event that the audio equipment switches to anoperation mode other than the optical disc operation mode from theoptical disc operation mode while reproducing the optical disc and thenswitches to the optical disc operation mode.

In accordance with the above construction, the optical disc apparatusaccording to the present invention thus constructed, mounted on anautomotive vehicle, can reproduce and stop reproducing informationrecorded on the optical disc in response to the operation mode selectedby way of the operation panel, and calculate reproduction timeinformation before resuming reproduction of the information recorded onthe optical disc. This leads to the fact that the optical disc apparatusaccording to the present invention thus constructed can obtain thereproduction time information after the operation mode is changed fromthe optical disc operation mode to the other operation mode and resumereproduction of the optical disc from the reproduction positionimmediately prior to the time point when the optical disc operation modechanged to the other operation mode in the event that the optical discoperation mode changed to the other operation mode and then returned tothe optical disc operation mode even while reproducing compression audiosignal recorded on the optical disc having no reproduction timeinformation in its address information.

BRIEF DESCRIPTION OF THE DRAWINGS

The features and advantages of an optical disc apparatus according tothe present invention will be more clearly understood from the followingdescription taken in conjunction with the accompanying drawings:

FIG. 1 is a block diagram showing a first embodiment of the optical discapparatus according to the present invention;

FIG. 2 is a flow chart showing an operation of resuming reproductionperformed by the optical disc apparatus shown in FIG. 1;

FIG. 3 is a block diagram showing constituent elements forming part of asecond embodiment of the optical disc apparatus according to the presentinvention;

FIG. 4 is a block diagram showing constituent elements forming part of athird embodiment of the optical disc apparatus according to the presentinvention;

FIG. 5 is a timing chart for explaining an operation of the optical discapparatus shown in FIG. 4;

FIG. 6 is a block diagram for showing constituent elements forming partof a fourth embodiment of the optical disc apparatus according to thepresent invention; and

FIG. 7 is a timing chart for explaining an operation of the optical discapparatus shown in FIG. 6.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The embodiments of the optical disc apparatus according to the presentinvention will be described hereinafter with reference to FIGS. 1 to 7of the drawings.

First Preferred Embodiment

FIG. 1 is a block diagram showing a construction of a first embodimentof the optical disc apparatus according to the present invention. Here,the optical disc apparatus 100 shown in FIG. 1 is intended to mean anapparatus for projecting a laser light to a pit formed on an opticaldisc 200 and detecting a reflection light reflected from the pit formedon the optical disc 200 to have the reflection light converted to aninformation signal to be reproduced therethrough. The optical disc 200may be constituted by, for example, a compact disc (hereinlater simplyreferred to as “CD”), a digital versatile disc (hereinlater simplyreferred to as “DVD”), and the like. It is assumed in the descriptionabout the present embodiment that the optical disc 200 is constituted bya CD for the purpose of simplicity but it is of course needless tomention that the optical disc 200 may be constituted by any otherstorage medium.

As shown in FIG. 1, the optical disc apparatus 100 shown as an opticaldisc apparatus according to the present invention comprises a spindlemotor 101 for driving the optical disc 200 to have the optical disc 200rotated, a spindle motor driving circuit 102 for controlling the spindlemotor 101 to have the spindle motor 101 rotated at a predeterminednumber of rotations per second, and an optical unit 103 including asemiconductor laser source, not shown, for projecting a light beam tothe optical disc 200 and a photoelectric conversion element, not shown,for receiving a reflection light reflected from the optical disc 200 tohave the reflection light converted to an electric signal.

The optical disc apparatus 100 further comprises a laser driving circuit104 for controlling the optical unit 103 to have the optical unit 103project the light beam at an arbitrary level, an objective lens 105intervening between the optical unit 103 and the optical disc 200 tohave the reflection light reflected from the optical disc 200 focused onthe photoelectric conversion element forming part of the optical unit103, an actuator unit 106 for actuating the objective lens 105, andactuator control means 107 for controlling the actuator unit 106 to havethe actuator unit 106 actuate the objective lens 105 between the opticalunit 103 and the optical disc 200. Here, the actuator unit 106 isconstituted by a focus actuator 106 a for actuating the objective lens105 to have an optical spot of the objective lens 105 moved along afocus direction parallel to an optical axis of the objective lens 105and a tracking actuator 106 b for actuating the objective lens 105 tohave the optical spot of the objective lens 105 moved along a radialdirection of a track of the optical disc 200.

The optical disc apparatus 100 further comprises an RF (radio frequency)circuit 108 for producing an RF signal and an error signal such as, forexample, a focus error signal, a tracking error signal, and the like,based on the electrical signal from the optical unit 103, a servocontrol circuit 109 for driving the spindle motor driving circuit 102and the actuator control means 107 to have the spindle motor drivingcircuit 102 and the actuator control means 107 respectively controlledbased on the error signal from the RF circuit 108, and a signalprocessing circuit 110 for converting the RF signal from the RF circuit108 into reproduction information such as, for example, soundinformation, image information and the like. Here, the signal processingcircuit 110 functions as signal processing means according to thepresent invention.

The optical disc apparatus 100 further comprises a DRAM (dynamic randomaccess memory) 111 for storing therein reproduction Information and thelike, a ROM (read only memory) 112 for storing therein a control programexecutable to control the whole operation of the optical disc apparatus100 and a central processing unit, hereinlater simply referred to as“CPU ” 113, for executing the control program stored in the ROM 112.Here, the DRAM 111 functions as parameter storage means according to thepresent invention, the ROM 112 and the CPU 113 collectively function asreproduction time computing means and optical disc reproduction meansaccording to the present invention to compute a reproduction time basedon parameters stored in the DRAM 111 and determine a reproduction startposition based on the parameters stored in the DRAM 111 after theoptical disc apparatus 100 is rebooted. The parameters stored in theDRAM 111 include, for example, but not limited to, information onaddress number, bit rate, monaural/stereo and the like. Here, it isassumed that the optical disc apparatus 100 is electrically connectedwith an automobile battery, a household power supply, an internal powersupply such as, for example, an internal battery, or the like to havepower uninterruptedly supplied at, not less than, a minimum level to theDRAM 111, the ROM 112, the CPU 113, and the like, which constituteessential constituent elements to carry out a function of resumingreproduction, while the optical disc apparatus 100 assumes an operationstop state in which a main power supply to the optical disc apparatus100 is turned off. While it has been described in the above that theparameter storage means is constituted by the DRAM 111 by way ofexample, it is needless to mention that the parameter storage means maybe constituted by any other storage medium such as, for example, a SRAM(static random access memory), a flash memory, an FRAM (ferroelectricRAM), or the like. The flash memory may include an EEPROM (electricallyerasable programmable ROM). It is preferable that the parameter storagemeans is constituted by a flash memory or an FRAM because of the factthat the parameter, the reproduction information, or the like remainsundeleted from the parameter storage means regardless of whether or notthe optical disc apparatus 100 assumes the operation stop state in whichthe main power supply to the optical disc apparatus 100 is turned off.

The, the operation of resuming reproduction performed by the presentembodiment of the optical disc apparatus 100 according to the presentinvention will be described hereinlater with reference to a flow chartshown in FIG. 2.

In step S101, the CPU 113 is operated to execute the control programstored in the ROM 112 to control the optical disc 200 to have theoptical disc 200 rotated. At this time, a reflection light reflectedfrom the optical disc 200 is converted by the optical unit 103 into anelectric signal. The electric signal is then converted into reproductioninformation by the RF circuit 108 and the signal processing circuit 110.

Step S101 goes forward to step S102, in which the CPU 113 is operated toexecute the control program stored in the ROM 112 to store parameterscontained in the reproduction information in the DRAM 111. In addition,the CPU 113 is operated to execute the control program stored in the ROM112 to update the parameters stored in the DRAM 111 whenever theparameters contained in the reproduction information have changed.

Step S102 goes forward to step S103, in which it is judged whether ornot a power supply, not shown, to the optical disc apparatus 100 isturned off. When it is judged that a power supply is not turned off,step S103 goes back to step S102. This means that the process in stepS102 is repeated until the power supply to the optical disc apparatus100 is failed or turned off. When, on the other hand, it is judged thatthe power supply is turned off, step S103 goes forward to step S104, inwhich the optical disc apparatus 100 is turned on and rebooted.

Step S104 goes forward to step S105, in which the CPU 113 is operated toexecute the control program stored in the ROM 112 to read out parametersstored in the DRAM 111 at the time point when the power supply wasturned off.

Step S105 goes forward to step S106, in which the CPU 113 is operated toexecute the control program stored in the ROM 112 to calculate areproduction time at the time point when the power supply was turned offbased on the parameters thus read from the DRAM 111 in accordance withan expression shown as bellows.

Monaural sound:Reproduction Time (sec.)={(the number of Addresses x number ofkb/address)/(Bit Rate (kbp/sec.))}/  1Stereo sound:Reproduction Time (sec.)={(the number of Addresses x number ofkb/address)/(Bit Rate (kbp/sec.))}/  2

The first expression is used for the optical disc of the monauralrecording format, while the second expression is used for the opticaldisc of the stereo recording format. The CPU 113 is operated to executethe control program stored in the ROM 112 to produce a control signal tohave a display unit, not shown, display the reproduction time thuscalculated.

Step S106 goes forward to step S107, in which the CPU 113 is operated toexecute the control program stored in the ROM 112 to calculate areproduction position at the time point when the power supply was turnedoff based on the parameters, such as, for example, parameters indicativeof the address number, stored in the DRAM 111 and produce a controlsignal to have the reproduction of the reproduction information such as,for example, audio data and image data resumed.

As will be seen from the foregoing description, it is to be understoodthat the present embodiment of the optical disc apparatus 100 can obtainthe reproduction time information after the power supply is restoredeven in the case that the power supply is turned off while reproducingcompression audio signal recorded on the optical disc having noreproduction time information in its address information, resulting fromthe fact that the present embodiment of the optical disc apparatus 100is operative to calculate the reproduction time based on the addressnumber, the bit rate, and the like, contained in the reproductioninformation.

Second Preferred Embodiment

FIG. 3 is a block diagram showing a construction of constituent elementsforming part of a second embodiment of the optical disc apparatusaccording to the present invention. The present embodiment of theoptical disc apparatus is shown in FIG. 3 as comprising the firstembodiment of the optical disc apparatus 100, not shown, and areproduction time displaying circuit 300. The reproduction timedisplaying circuit 300 includes a liquid crystal display 302 and LCD(liquid crystal display) driving circuit 301 for driving the liquidcrystal display 302.

As shown in FIG. 3, the first embodiment of the optical disc apparatus100 is operatively connected to the reproduction time displaying circuit300 to ensure that the LCD driving circuit 301 is operative to receiveinformation from the CPU 113. This leads to the fact that thereproduction time information calculated by the CPU 113 is outputted tothe LCD driving circuit 301. The LCD driving circuit 301 is operative todrive the liquid crystal display 302 to have the liquid crystal display302 display the reproduction time based on the reproduction timeinformation thus inputted from the CPU 113.

As will be seen from the foregoing description, it is to be understoodthat the present embodiment of the optical disc apparatus can obtain thereproduction time information as well as have the reproduction timedisplaying means (reproduction time displaying circuit) display thereproduction time after the power supply is restored even in the casethat the power supply is turned off while reproducing compression audiosignal recorded on the optical disc having no reproduction timeinformation in its address information, resulting from the fact that thepresent embodiment of the optical disc apparatus is operative tocalculate the reproduction time based on the address number, the bitrate, and the like, contained in the reproduction information.

Third Preferred Embodiment

FIG. 4 is a block diagram showing a construction of constituent elementsforming part of a third embodiment of the optical disc apparatusaccording to the present invention. The present embodiment of theoptical disc apparatus is mounted on an automotive vehicle, andcomprising the first embodiment of the optical disc apparatus 100. Asshown in FIG. 4, in the present embodiment of the optical disc apparatusaccording to the present invention, the CPU 113 forming part of thefirst embodiment of the optical disc apparatus 100 is operative to inputan ACC ON/OFF signal indicative that an ignition key of the automotivevehicle is turned on or off. As shown in FIG. 5, the ACC ON/OFF signaldesignated by “ACC” remains at a high level while power is supplied froman accessory power supply (ACC power supply) and the present embodimentof the optical disc apparatus is capable of reproducing informationrecorded on the optical disc. The ACC ON/OFF signal, on the other hand,remains at a low level while the accessory power supply is turned offand the present embodiment of the optical disc apparatus is unable toreproduce information recorded on the optical disc.

Here, it is assumed that the control program stored in the ROM 112includes a control program executable to control the whole operation ofthe present embodiment of the optical disc apparatus in the case thatthe ACC ON/OFF signal changes from one of the low and high levels to theother as a result of the operation of the ignition key.

The CPU 113 is designed to input the ACC ON/OFF signal. The CPU 113operated to carry out the following operation in accordance with thecontrol program stored in the ROM 112.

The CPU 113 is operated to have the optical disc apparatus reproduce theinformation recorded on the optical disc while the CPU 113 inputs theACC ON/OFF signal at the high level. The CPU 113, on the other hand, isoperated to control the optical disc apparatus to have the optical discapparatus stop reproducing the information recorded on the optical discwhen the CPU 113 inputs the ACC ON/OFF signal at the low level. Thismeans that power fails to be supplied to constituent elements such asthe spindle motor 101, the optical unit 103, and the like, other thanthe CPU 113, the ROM 112, and the DRAM 111 in the case that theaccessory power supply is turned off and thus the ACC ON/OFF signalchanges from the high level to the low level as a result of the factthat the ignition key is turned off. The operation performed by thepresent embodiment of the optical disc apparatus when the power supplyis turned off is the same as the operation described about the firstembodiment.

When power is recovered from the accessory power supply and the ACCON/OFF signal changes from the low level to the high level as a resultof the fact that the ignition key is turned on and power is restored tothe constituent elements such as the spindle motor 101, the optical unit103, and the like, to which power has failed to be supplied since thetime point when the reproduction operation of the optical disc wasstopped. Simultaneously, the CPU 113 is operated to read out theinformation stored in the DRAM 111 at the time point when the ACC ON/OFFsignal changed from the high level to the low level to calculatereproduction time information, and have the reproduction of the opticaldisc started from a reproduction position at the time point when theaccessory power supply has turned off and the reproduction operation ofthe optical disc was stopped. Thus, the reproduction operation of theoptical disc is resumed.

The operation performed by the present embodiment of the optical discapparatus when the ignition key is operated will be described withreference to FIG. 5.

As shown in FIG. 5, power is supplied from the accessory power supply instates S1 and S3. In the state S1, information recorded on the opticaldisc is reproduced and the ACC ON/OFF signal remains at the high level.At a time point when the reproduction time is T1, the ignition key isturned off to have the accessory power supply turned off, and the ACCON/OFF signal changes from the high level to the low level as will beclearly seen from FIG. 5. This means that the optical disc apparatuschanges from the state S1 to the state S2 and the reproduction operationof the optical disc was stopped at the time point when the reproductiontime is T1. The state S2 changes to the state S3 when the ignition keyis turned on to have the accessory power supply turned on, and the ACCON/OFF signal changes from the low level to the high level to have thereproduction of the optical disc started from the reproduction time T1at the time point when the accessory power supply has turned off and thereproduction operation of the optical disc was stopped. The operationsperformed by the CPU 113 when the state S1 changes to the state S2 andthe state S2 changes to the state S3 have been described in the aboveand thus will not be described.

As will be seen from the foregoing description, it is to be understoodthat the present embodiment of the optical disc apparatus is operativeto reproduce and stop reproducing information recorded on the opticaldisc whenever the ignition key is operated and the accessory powersupply is turned on and off, and calculate a reproduction time at thetime point when the ignition key was turned off and thus the accessorypower supply was turned off before resuming reproduction of theinformation recorded on the optical disc. This leads to the fact thatthe present embodiment of the optical disc apparatus can obtain thereproduction time information after the power supply is restored andresume reproduction of information even in the case that the powersupply is turned off while reproducing compression audio signal recordedon the optical disc having no reproduction time information in itsaddress information.

Fourth Preferred Embodiment

FIG. 6 is a block diagram showing a construction of constituent elementsforming part of a fourth embodiment of the optical disc apparatusaccording to the present invention. The present embodiment of theoptical disc apparatus according to the present invention is mounted onan automotive vehicle and operatively connected to an in-vehicle audioequipment 601 operative to selectively assume a plurality of operationmodes including an optical disc operation mode having the optical discreproduced. The present embodiment of the optical disc apparatus isadapted to resume reproduction of information recorded on the opticaldisc when the in-vehicle audio equipment 601 switches to the opticaldisc operation mode from an operation mode other than the optical discoperation mode. As shown in FIG. 6, the in-vehicle audio equipment 601comprises a CPU 602, a tuner unit 603 shown as an example of an audiodevice, a selector unit 604, an amplifying unit 605, a speaker unit 606,and an operation panel 607 in addition to the first embodiment of theoptical disc apparatus 100. It is herein assumed that the in-vehicleaudio equipment 601 is operative to selectively assume a plurality ofoperation modes including an optical disc operation mode having theoptical disc apparatus 100 reproduce information recorded on the opticaldisc, and a tuner operation mode having the tuner unit 603 reproduceinformation.

The operation panel 607 is designed to have an operator select anoperation mode. The CPU 602 is adapted to produce an operation modesignal indicative of the operation mode to be outputted to the CPU 113forming part of the optical disc apparatus 100, the tuner unit 603, andthe selector unit 604. The CPU 113 forming part of the optical discapparatus 100 is operative to have the reproduction of the optical discstarted in response to the operation mode signal indicative of theoptical disc operation mode, hereinlater simply referred to as an“optical disc operation mode signal”. The CPU 113 forming part of theoptical disc apparatus 100, on the other hand, is operative to have thereproduction of the optical disc stopped in response to the operationmode signal indicative of the tuner operation mode, hereinlater simplyreferred to as a “tuner operation mode signal”.

The selector unit 604 is operative to have the optical disc apparatus100 supply an output signal to the amplifying unit 605 in response tothe optical disc operation mode signal. The amplifying unit 605 isoperative to amplify the output signal from the selector unit 604. Thespeaker unit 606 is operative to convert the output signal thusamplified into a sound. The selector unit 604, on the other hand, isoperative to have the tuner unit 603 supply an output signal to theamplifying unit 605 in response to the tuner operation mode signal. Theamplifying unit 605 is operative to amplify the output signal from theselector unit 604.

As shown in FIG. 7, the operation mode signal remains at a high level instates S1 and S3, in which the operation mode signal is indicative ofthe optical disc operation mode, while, on the other hand, the operationmode signal remains at a low level in a state S2, in which the operationmode signal is indicative of the tuner operation mode. Informationrecorded on the optical disc is reproduced until a time point when thereproduction time is T1. At the time point when the reproduction time isT1, the operation mode signal changes from the high level to the lowlevel. This means that the optical disc apparatus changes from the stateS1 to a state S2 and the reproduction operation of the optical disc wasstopped at the time point when the reproduction time is T1. When theoperation mode signal changes from the low level to the high level (whenthe state S2 changes to the state S3), the reproduction of the opticaldisc is resumed from the reproduction time T1. In general, power supplyto the tuner unit 603 is turned off in the optical disc operation mode.On the other hand, power is uninterruptedly supplied to the CPU 113, theROM 112, and the DRAM 111 while power supply to power consuming circuitssuch as, for example, driving circuits are turned off in the tuneroperation mode as described in the above to have the optical disc stoprotating and the actuator stop operating.

As will be seen from the foregoing description, it is to be understoodthat the present embodiment of the optical disc apparatus is mounted onan automotive vehicle and operative to reproduce and stop reproducinginformation recorded on the optical disc in response to the operationmode selected by way of the operation panel, and calculate reproductiontime information before resuming reproduction of the informationrecorded on the optical disc. This leads to the fact that the presentembodiment of the optical disc apparatus can obtain the reproductiontime information after the operation mode is changed and resumereproduction of the optical disc from the reproduction positionimmediately prior to the time point when the optical disc operation modechanged to the tuner operation mode in the event that the optical discoperation mode changed to the tuner operation mode and then the tuneroperation mode changed to the optical disc operation mode even in thecase that the present embodiment of the optical disc apparatus isoperative to reproduce compression audio signal recorded on the opticaldisc having no reproduction time information in its address information.

INDUSTRIAL APPLICABILITY OF THE PRESENT INVENTION

In view of the foregoing description, it is to be understood that theoptical disc apparatus according to the present invention can attain aneffect of obtaining the reproduction time information after the powersupply is restored in the event that power supply is turned off whilereproducing compression audio signal recorded on the optical disc havingno reproduction time information in its address information, and isavailable for the optical disc apparatus and the like for resuming thereproduction of compression audio signal recorded on the optical discbased on the obtained reproduction time information.

1. An optical disc apparatus, comprising: an optical unit for projectinga laser light to an optical disc having a plurality of addresses andconverting a reflection light reflected from said optical disc into anelectrical signal, said electrical signal including a plurality of bits;signal processing means for processing said electrical signal at apredetermined bit-rate from said optical unit to have said electricalsignal converted into reproduction information required forreproduction; parameter storage means for storing therein a plurality ofparameters contained in said reproduction information from said signalprocessing means, said parameters including the bit-rate and a number ofaddresses from the plurality of addresses processed by the signalprocessing means; reproduction time computing means for computing areproduction time based on said plurality of parameters stored in saidparameter storage means, wherein the reproduction time is a point intime; and optical disc reproduction means for determining a reproductionstart position based on said plurality of parameters stored in saidparameter storage means.
 2. An optical disc apparatus as set forth inclaim 1, which further comprises: reproduction time displaying means fordisplaying said reproduction time based on information on saidreproduction time computed by said reproduction time computing means. 3.An optical disc apparatus as set forth in claim 1, which is mounted onan automotive vehicle, and in which said reproduction time computingmeans is operative to read out said parameter stored in said parameterstorage means to calculate a reproduction time at the time point when anaccessory power supply was turned off and said optical disc reproductionmeans is operative to determine a reproduction start positionsubstantially at the time point when said accessory power supply wasturned off, in the event that said accessory power supply was turned offwhile reproducing said optical disc and then turned on.
 4. An opticaldisc apparatus as set forth in claim 1, operatively connected to anaudio equipment operative to selectively assume a plurality of operationmodes including an optical disc operation mode having said optical discreproduced, and in which said reproduction time computing means isoperative to read out said parameter stored in said parameter storagemeans to calculate a reproduction time at the time point when said audioequipment switches to an operation mode other than said optical discoperation mode from said optical disc operation mode and said opticaldisc reproduction means is operative to determine a reproduction startposition substantially at the time point when said audio equipmentswitches an operation mode other than said optical disc operation modefrom said optical disc operation mode, in the event that said audioequipment switches to an operation mode other than said optical discoperation mode from said optical disc operation mode while reproducingsaid optical disc and then switches to said optical disc operation mode.